(S)-2-(4-Methoxy-benzyloxy)-4-methyl-pentanoic acid (E)-(1S,2R)-1-{(E)-3-[(R)-2-(4-methoxy-phenyl)-1-(2-trimethylsilanyl-ethoxycarbonyl)-ethylcarbamoyl]-allyl}-2-methyl-4-phenyl-but-3-enyl ester